Inserter systems, such as those applicable for use with the present invention, are typically used by organizations such as banks, insurance companies and utility companies for producing a large volume of specific mailings where the contents of each mail item are directed to a particular addressee. Also, other organizations, such as direct mailers, use inserts for producing a large volume of generic mailings where the contents of each mail item are substantially identical for each addressee. Examples of such inserter systems are the 8 series, 9 series, and APST™ inserter systems available from Pitney Bowes Inc. of Stamford, Conn.
In many respects, the typical inserter system resembles a manufacturing assembly line. Sheets and other raw materials (other sheets, enclosures, and envelopes) enter the inserter system as inputs. Then, a plurality of different modules or workstations in the inserter system work cooperatively to process the sheets until a finished mail piece is produced. The exact configuration of each inserter system depends upon the needs of each particular customer or installation.
Typically, inserter systems prepare mail pieces by gathering collations of documents on a conveyor. The collations are then transported on the conveyor to an insertion station where they are automatically stuffed into envelopes. After being stuffed with the collations, the envelopes are removed from the insertion station for further processing. Such further processing may include automated closing and sealing the envelope flap, weighing the envelope, applying postage to the envelope, and finally sorting and stacking the envelopes.
The input stages of a typical inserter system are depicted in FIG. 1. At the input end of the inserter system, rolls or stacks of continuous printed documents, called a “web,” are fed into the inserter system by a web feeder 10. The web is often comprised of two sheets printed side-by-side across the width of the web. The continuous web must be separated into individual document pages. This separation is typically carried out by a web cutter 20 that cuts the continuous web into individual document pages. Downstream of the web cutter 20, a right angle turn 30 may be used to reorient the documents, and/or to meet the inserter user's floor space requirements.
The separated sheets must subsequently be grouped into collations corresponding to the multi-page documents to be included in individual mail pieces. This gathering of related document pages occurs in the accumulator module 40 where individual pages are stacked on top of one another.
The control system for the inserter senses markings on the individual pages to determine what pages are to be collated together in the accumulator module 40. In a typical inserter application, mail pieces may include varying numbers of pages to be accumulated.
Downstream of the accumulator 40, a folder 50 typically folds the accumulation of documents, so that they will fit in the desired envelopes. To allow the same inserter system to be used with different sized mailings, the folder 50 can typically be adjusted to make different sized folds on different sized paper. As a result, an inserter system must be capable of handling different lengths of accumulated and folded documents.
Downstream of the folder 50, a buffer transport 60 transports and stores accumulated and folded documents in series in preparation for transferring the documents to the synchronous inserter chassis 70.
In a typical embodiment of a prior art web cutter 20, the cutter is comprised of a guillotine blade that chops transverse sections of web into individual sheets. This guillotine arrangement requires that the web be stopped during the cutting process.
A frequent limitation on speed of an inserter system is the ability of the system to handle all of the generated documents if the system is required to stop. An input system may be capable of going very fast under non-stop operating conditions, but a problem arises during stopping if there isn't a means to handle all the sheets produced by the input system. Thus in designing input stages to an inserter system, a consideration is to provide a place for all “work-in-progress” sheets and collations, assuming that the system may be required to stop at any time. A buffer module such as the ones described in U.S. Pat. Nos. 6,687,569 and 6,687,570 issued Feb. 3, 2004 and assigned to the assignee of the present application, may be used to provide stopping stations, or “parking spots,” for work-in-progress documents.
For proper operation, an inserter input system should not be run faster than spaces for holding work in progress can be made available. For mail runs including mail pieces having larger numbers of sheets, the problem is less severe since sheets from the same mail piece are stored together in the buffer stations. For mail runs with mail pieces only having a few sheets, the ratio of required stopping stations to the number of sheets generated will be greater, and the inserter input may be required to slow down, or to pause.
For existing systems with webs having “2-up” side-by-side sheets, some additional logic has been used to control cutting and to facilitate throughput. This logic is applicable when a set of 2-up sheets is presented to the guillotine cutter for cutting, and at least one of the sheets belongs to a new collation to be started.
If both of the 2-up sheets belong to the same collation, and if there is an available parking spot, then both sheets are cut in a continuous stroke of the guillotine cutter.
If the sheets in the set are from different collations then two single cuts are performed. The first cut is done by a partial cutting operation. As is known in the art, a guillotine blade can be also be used to perform a partial cut across the width of the web. This is accomplished by partially lowering the sloped blade, as seen in FIGS. 4A-4C. In prior art systems, a gap was always required between sheets belonging to different collations. Thus, if the sheets belong to different collations, the prior art systems required that the sheets from different collations be cut and fed separately in this partial cut manner. After the desired gap has been achieved, the second sheet is cut by fully lowering the guillotine blade, so that the remaining sheet is separated and carried away. If there is no additional parking spot available, only the first sheet is cut, and the guillotine blade pauses until a parking spot is available before finishing the single cutting of the second sheet.